Inks



Patented Oct. 10, 1950 INK'S.

Andries Voet, New York, N. Y., assignor to J. M.

Huber Corporation, Locust, N. J a corporation of New Jersey I NoDrawing.Applicationseptember.23,194,7, SerialNo. 775,743 t 1 ljThis inventionrelates to inks and more par- Many inks, even when substantially dry,leave, 5

surfaces which have considerable tack so that they-,adheretoothersi-milar surfaces particuilarlywhen slightlywarm or when underpressure 1511011 as-that obtained ,at the bottom 0f ,a pileof sheets ofpaper. Heat set inks usually contain binding agents of a waxy orresinous nature, such 'as asphalts or resins, which are thermoplastic:and tend to give adherent-surfaces.

inks often contain rosin, modified rosin or soluble phenolic resinswhich are'not only thermoplastic but which leave surfaces havingconsiderable tack. Asphaltic substances and rosins also are commonconstitutents of gravure inks. In all these cases, the solvent isusually a material .of controlled volatility, such as certain petroleumfractions, or a material" which is, sufficiently 'misciblewith water sothat the dissolved material may be precipitated from the solvent by theapplication of water in some suitable form.

Many of the above types of inks have been uns satisfactory also becauseof the'chemical activity of the binding agents. This is particularlytrue of some of the modified rosins which are acidic in 'natu're.Furthermore, some of the phenolic resins have an odor which is verypersistent and objectionable.

It is an object of the present invention to provide inks having a novelbinding material which are useful for a wide variety of purposes. Afurther object is to provide inks having a binding material which leavesanon-thermoplastic film of a non-tacky nature. A still further object isto provide inks based on non-drying vehicles which contain a bindingmaterial and which may be quickly set toJl-eave non-tacky printedsurfaces. Other objects are to provide new compositions of matter and toadvance the art. Still other object s will appear hereinafter.

The above and other objects may be accomplished in accordance with myinvention which comprises the provision of an ink characterized by anorganic water-miscible solvent in which lignin is soluble to the extentof at least 5% by weight, a pigment and a lignin-which is dissolved inthe solvent and. serves as the binding material.

-I have found that lignin may be brought into a such as heat or bycontact with water, w ll l av 19 Claims. (o1'.'1ds 30),

Water set,

'ganic water-miscible solvents. solvent is one in which the lignin issolubleto the a film of a-particularlyjdry nature which has'littletendency to adhere to other similar films under pressure. Thelignin is infusible and the films formed iby it-are non-thermoplasticand hence will not become tacky when warmed;

Lignin is a substance which occurs along with the cellulose, the sugarsubstances and the resins in woody fibers. It is extracted fromwood-during the processof making-paper'pulp and re- ,mains in the blackliquor after the separation of the talloil. Common methods forthe'prepara- .tion of paper pulp are the alkali process and the sulfateprocess, bothof which-produce. lignin ,which is insoluble in water butsoluble in alkaline solutions; That obtained by the sulfateprocess isknown as sulfate lignin. That obtained by the alkali process is knownas'alkali lignin and, when the alkali is sodium, frequently as sodiumDerivatives of' lignin I have found that lignin is'soluble in many or-Prefer'ably, "the 5% by weight;

Suitable solvents are the glycols, ethers of the glycols, esters of theglycols', 2 -meth'yl 2 4- pentanediol, formamide. pyridine, methyl ethylketone. and the like. The glvcols', their ethers and esters willgenerally be preferred, including the poly glycols. However, polyglycols having a molecular wei ht of about 600 and above are not watermiscible and hence-will not be i's'uitsable. Representative 'gly'colswhich are satisfactory, and in which lignin is solublejto the extent ofat least 40% by'weight at 30 0., are ethylene glycol, diethylene glycol,'cellosolve,

butyl cellosolve. monobutyl ether ofethylene glycol, monomethyl ether ofethylene glycol, ,monoethylether of ethylene." glycol, m'onom'ethyl.ether of diethylene glycol, monoethyl ether-of diethylene glycol,monobutyl ether of diethylene y ol, et ylene glycolmonomethylethersacea; 1 tate, diethylene glycol monoethyl ether acetateand triethylene glycol methyl ether acetate. Lignin is soluble inZ-methyl 2-4-pentanediol to the extent of about 25% by weight. Lignin issoluble in formamide, pyridine and methyl ethyl ketone to the extent ofa little more than 5% by weight.

The pigment may be any pigment of the type usually employed in inks andlike coloring materials. Such, pigments include carbon black titaniumdioxide, red pigment, milori blue and the like. My invention isparticularly applicable to the production of carbon black inks.

The amount of pigment will be that ordinarily used to provide inks ofthe desired color and viscosity. 'Uusually the pigment will be employedin the proportion from about 2% to about 60% by weight base on thesolvent. In the case of carbon black the amount will be from about 2% toabout 31% by weight based on the solvent and preferably from about 9% toabout 31%.

The amount of lignin employed will correspond to the amount ofbinding-material ordinarily employed in inks. The lignin will usually beemployed in the -proportion of from 1 part to about 5 parts by weight toeach part of pigment. Larger amounts of pigment may be used but withoutadvantage.

In some cases it may be desirable t improve the continuity of the filmobtained and to increase the tackiness'of the films. This may beaccomplished by incorporating a resin in the ink tothe extent requiredto produce the desired results. Any of the resins usually employed ininks and like compositions maybe employed for this purp se. I preferablyemploy gum rosin or wood rosin for such purpose. The incorporation ofrosin in the ink up to about of the weight of the lignin will increasethe continuity of the film but will have but little eifect on the tackof the film left by the ink. Increasing amounts'o'f rosin will increasethe tack of the film and I contemplate employing rosin in the proportionof from about 25% to about 300% of the weight of the lignin for thispurpose. Such amounts of rosin will not render the film unde irablytacky.

Where the ink films are to be set by means of water'the composition canbe varied in such a manner that it will be @more easily preci itated byincorporating therein a material which is sensitive towater such as gumrosin and the aliphatic hydrocarbon-ins luble portion of wood rosin. Theamount of such water sensitizing material to be employed will dep ndupon the sensitivity desired, the water sensitivity of the particularmaterial and the solvent. 1

In order to more clearly illustrate my invention, the preferred modes ofcarrying it'into effect, and the advantageous results to be obtainedthereby the following examples are given:

Example I 1 1 00 parts of alkali lignin were dissolved by stirring into100 parts of diethylene glycol at roughly and afterward refining it bymeans of a 7 three rollermill of the standard type employed In the paintof ink industry. When printed, this ink was set by the application ofwater (by flowung'water across the surface of the printed sheet forabout 2'seconds) to give a nontacky Example II parts of sulfate ligninwere dissolved in 235 parts of ethylene glycol at about 100 C. 25 partsof carbon black were added and the ink was refined on a three rollermill. This ink was printed and quickly dried by means of radiant heat togive a well fixed and nontacky film.

Example III Example IV '19 parts of sulfate lignin and 15 parts of gumrosin were dissolved in 48 parts of diethylene glycol to form anink'varnish. This was pigmented with 15 parts of channel carbon and 3parts of milori blue. This constitutes an ink which is suflicientlysensitive towater to be easily precipitated to give nontacky printedsheets.

In a similar .manner, the aliphatic hydrocarhon-insoluble portion ofwood rosin may be used along with the lignin to decrease the watertolerance.

It will be understood that the preceding examples are given forillustrative purposes solely and that my invention is not intended to belimited to the specific embodiments disclosed therein. It will beapparent to those skilled in the art that many variationsand'modifications can'be made, particularly in the pigments and solventsemployed and in the modes of application of the inks. For example, theinks may be water set by employing a fine spray to wet the surface ofthe printed sh'ee't or the sheet maybe contacted withcsteam in a steam'chamber or by other methods knownto the art; Mixtures of two or more ofthe rsolvents'may be employed. Likewise, other methods, than thethreeroll mill, maybe employed for incorporating thepigment 'in the solvent,including mixture of the pigment with part or all of the lignin'beforeincorporation in the solvent. Also, other well-known water sensitizingagentsmay be employed in place of those specifically disclosed. Inaddition, various other materials, ordinarilyemployed for modifying theviscosity, stability, flow characteristics and like properties of inks,may be incorporated.

It will be apparent that,-by my invention, I have provided new andvaluable inks having many novel and desirable properties andparticularly inks which will leave films varying from non-thermoplasticnontacky films to substantially tacky .films, thetackiness of which canbe readily controlled. At the same time, Ihave employed a cheap andabundant material, lignin, which has been discardedias waste material inlarge quantities. The inks of my invention are particularly suitable.for use on surfaces which have a slight porosity such as paper,leather, wood, cloth and the like. By the use of my invention, it ispossible to provide a large variety of inks having a wide utility.

I claim:

1. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen and in which ligninis soluble to'th 'ext ntof atleast 5% byweight. a pi m t in the proportion of from about 2% to about 60% byweight based on the solvent, and lignin in the proportion of from 1 partto about parts by weight to each part of pigment.

2. An ink consisting essentially of a watermiscible-neutral aliphaticsolvent containing from 2 to 8 carbon atomsand only carbon, hydrogen andoxygen and in which lignin is soluble to the extent of at least 40% byweight, a pigment in the proportion of from about 2% to about 60% byWeight based on the solvent, and lignin in the proportion of from 1 partto about 5 parts by weight to each part of pigment.

3. An ink consisting essentially of a Watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen and in which lignin is soluble to the extent of at least 5%by weight, carbon black in the proportion of from about 2% to about 31%by weight based on the solvent, and lignin in the proportion of from 1part to about 5 parts by weight to each part of carbon black.

4. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen and in which lignin is soluble to the extent of at least 10%by weight, carbon black in the proportion of from about 9% to about 31%by weight based on the solvent, and lignin in the proportion of from 1part to about 5 parts by Weight to each part of carbon black.

5. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen which is a member of the class consisting of glycols, ethersof glycols and esters of glycols and in which lignin is soluble to theextent of at least 40% by weight, carbon black in the proportion of fromabout 2% to about 31% by weight based on the solvent, and lignin in theproportion of from 1 part to about 5 parts. by weight to each part ofcarbon black.

6. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen which is a member of the class consisting of glycols, ethersof glycols and esters of glycols and in which lignin is soluble to theextent of at least 40% by weight, carbon black in the proportion of fromabout 9% to about 31% by weight based on the solvent, and lignin in theproportion of from 1 part to about 5 parts by weight to each part ofcarbon black.

7. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hy-

drogen and oxygen which is a member of the class consisting of glycols,ethers of glycols and esters of glycols and in which lignin is solubleto the extent of at least 5% by weight, a pigment in the proportion offrom about 2% to about 60% by weight based on the glycol, and lignin inthe proportion of from 1 part to about 5 parts by weight to each part ofpigment.

8. An ink consisting essentially of a watermiscible glycol in whichlignin is soluble to the extent of at least 40% by weight, a pigment inthe proportion of from about 2% to about 60% by weight based on theglycol, and lignin in the proportion of from 1 part to about 5 parts byweight to each part of pigment.

9. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen which is a member of the 6. class consisting of glycols,ethers and glycols and esters of glycols and in which lignin is solubleto the extent of at least 5% by weight, carbon black in the proportionof from about 2% to about 31% by weight based on the glycol, and ligninin the proportion of from 1 part to about 5 parts by weight to each partof carbon black.

10. An ink consisting essentially of a Watermiscible glycol in whichlignin is soluble to the extent of at least 10% by weight, carbon blackin the proportion of from about 9% to about 31% by weight based on theglycol, and lignin in the proportion of from 1 part to about 5 parts byweight to each part of carbon black.

11. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen which is a member of the class consisting of glycols, ethersof glycols and esters of glycols and in which lignin is soluble to theextent of at least 40% by weight, carbon black in the proportion of fromabout 2% to about 31% by weight based on the glycol, and lignin in theproportion of from 1 part'to about 5 parts by weight to each part ofcarbon black.

12. An ink consisting essentially of a watermiscible glycol in whichlignin is soluble to the extent of at least 40% by weight, carbon blackin the proportion of from about 9% to about 31% by weight based on theglycol, and lignin in the proportion of from 1 part to about 5 parts byWeight to each part of carbon black.

13. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen and in which lignin is soluble to the extent of at least 5%by weight, a pigment in the proportion of from about 2% to about 60% byweight based on the solvent, and lignin in the proportion of from 1 partto about 5 parts by weight to each part of pigment, and rosin in theproportion of from about to about 300% by weight based on the lignin.

14. An ink consisting essentially of an organic water-miscible neutralaliphatic solvent containing from 2 to 8 carbon atoms and only carbon,hydrogen and oxygen and in which lignin is soluble to the extent of atleast by weight, a pigment in the proportion of from about 2% to aboutby weight based on the solvent, and lignin in the proportion of from 1part to about 5 parts by weight to each part of pigment, and rosin inthe proportion of from about 25% to about 300% by weight based on thelignin.

15. An ink consisting essentially of a watermiscible neutral aliphaticsolvent containing from 2 to 8 carbon atoms and only carbon, hydrogenand oxygen which is a member of the class consisting of glycols, ethersof glycols and esters of glycols and in which lignin is soluble to theextent of at least 40% by weight, carbon black in the proportion of fromabout 9% to about 31% by weight based on the glycol, and lignin inproportion of from 1 part to about 5 parts by weight to each part ofcarbon black, and rosin in the proportion of from about 25% to about300% by weight based on the lignin.

16. An ink consisting essentially of diethylene glycol, a pigment in theproportion of from about 2% to about 60% by weight based on thediethylene glycol, and lignin in the proportion of from 1 part to about5 parts by weight to each part of pigment.

17. An ink consisting essentially of diethylene about 2% to about 31% byweight based on the diethylene glycol, and lignin in the proportionloffrom 1 part to about 5 parts by weight to each' part of carbon black.

18. An ink consisting essentially of ethylene glycol, a pigment in theproportion of from aboutv 2% to-about 60% by weight based on theethylene from 1 part to about 5 parts by weight to each 15 part ofcarbon black.

' ANDRIES VO'ET.

REFERENCES CITED UNITED STATES PATENTS Number Name 7 Date 1,860,043Ludwigsen May 24, 1932 2,242,601 Wallace May 20, 1941 2,327,596 Ericksonet a1 Aug. 24, 1943 10 2,377,709 Meunier June 5, 1945 FOREIGN PATENTSNumber Country Date 248,834 Great Britain Mar. 10, 1926 OTHER REFERENCESMitchel et al.: Inks, Their Composition and' Manufacture, (1916),pages14'7 to 150.

1. AN INK CONSISTING ESSENTIALLY OF A WATERMISCIBLE NEUTRAL ALIPHATICSOLVENT CONTAINING FROM 2 TO 8 CARBON ATOMS AND ONLY CARBON HYDROGEN ANDOXYGEN AND IN WHICH LIGNIN IS SOLUBLE TO THE EXTENT OF AT LEAST 5% BYWEIGHT, A PIGMENT IN THE PROPORTION OF FROM ABOUT 2% TO ABOUT 60% BYWEIGHT BASED ON THE SOLVENT, AND LIGNIN IN THE PROPORTION OF FROM 1 PARTTO ABOUT 5 PARTS BY WEIGHT TO EACH PART OF PIGMENT.